Re: [libvirt] [PATCH] Fix off-by-1 in QEMU boot arg array handling

On Tue, Aug 24, 2010 at 12:02:38PM +0100, Daniel P. Berrange wrote:
> A QEMU guest can have upto VIR_DOMAIN_BOOT_LAST boot entries
> defined. When building the QEMU arg, each entry takes a
> single byte. This means the array must be declared to be
> VIR_DOMAIN_BOOT_LAST+1 bytes in length to allow for the
> trailing null
FYI, This bug was introduced by me 2 years ago during the conversion
to common domain APIs. In 6385fe3edebf4593b6dc08eee086f73dcc71b43d.
We already have a test case that covers this precise boundary
condition, but it has never exhibited a problem, even under valgrind.
In Fedora 15 rawhide though, there is more advanced GCC array bounds
checking present and this causes a runtime abort in the test suite.
Nice example of why running 'make check' in the RPM spec is good :-)
Regards,
Daniel
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